This invention pertains to means for detecting the wheel speed of a vehicle by producing a voltage corresponding to, or proportional to the speed, or a series of on and off pulses at a voltage chosen by the customer, and in particular to a speed sensor which is incorporated with a fluid seal, such as the output seal on the transmission case of a vehicle, into an assembly of both the seal and the sensor.
Known speed sensors, in front wheel drive automobiles, are typically located at the wheel ends of the axle. The standard sensor is a variable reluctance type that senses a tone wheel or gear tooth pressed onto the shaft. In order to assure the accuracy of this type of sensor, the shaft must be machined specially to adhere to specifications of the axle manufacturers. Also, the known sensor systems require adjustment, after installation, to insure an air gap in the operating range of the sensor. Further, heat from the brakes can push the sensor beyond the upper limits of its safe operating range.
The foregoing illustrates limitations known to exist in present speed sensing devices. Thus, it is apparent that it would be advantageous to provide alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.